A supercharger is commonly installed on a vehicle internal combustion engine to provide air at high pressure into the engine's intake manifolds. The primary purpose of this added, high pressure air is to increase engine power output, i.e. engine horsepower. However, most superchargers are driven by the engine itself and, as a result, when the supercharger is operational, the engine must work harder. This causes a reduction in engine efficiency, more fuel is consumed, and there are more emissions. There is also increased wear and tear on engine components. These factors have kept superchargers off many vehicles and, for motorists who still have superchargers in use on their engines, caused them added expense for fuel and parts.
To address these problems, when an internal combustion engine is provided with a mechanical supercharging system, the supercharger blower is attached to the engine crankshaft by a supercharger clutch assembly. When the engine is operated under lower load or other conditions in which supercharging is not required, the clutch assembly is disconnected to cease operation of the supercharger. This reduces power loss resulting from supercharger operation and improves fuel economy. The supercharger stays cooler and there is less wear and tear on the engine, as well as the supercharger. When supercharging is required, the clutch assembly is engaged and the supercharger again becomes operational.
There have been prior attempts to control supercharger operation by means of mechanical and electromagnetic clutch systems. However, these prior attempts have been shown to be inefficient or problematic in actual operation. Many also involve complex mechanisms which must be integrally incorporated into the vehicle engine.